Principal diagnosis cubes for 1993–94 to 2013–14

The principal diagnosis is defined as the diagnosis established after study to be chiefly responsible for occasioning the patient’s episode of care in hospital. In some cases, the principal diagnosis is described in terms of a treatment for an ongoing condition (for example, care involving dialysis or rehabilitation).

Six data cubes are available on the principal diagnosis of patients admitted to Australian hospitals:

Notes

The use of the different editions in the data cubes means that data across years may not be exactly comparable.

The variables in the data cubes are:

Year

Sex (Male, Female, Other/Not reported)

Age group (5 year groupings, i.e. <1, 1–4, 5–9,10–14,...85+, Not reported)

Same day (Same day/non-same day)

Principal diagnosis

The measures (values ) in the data cubes are:

Total separations

Patient days

Average length of stay (ALOS)

Within the cubes, users can view the diagnoses by using a pull-down menu and can work down from the broad chapter level in the ICD classifications to more specific categories (i.e. principal diagnosis code), as illustrated below:

ICD Chapter

ICD Sub-Chapter

ICD 3-character code

ICD 4-character code (where relevant)

ICD 5-character code (where relevant)

For example:

Endocrine, nutritional and metabolic diseases (E00-E89)

Impaired glucose regulation and diabetes mellitus (E00-E14)

Type 2 diabetes mellitus (E11)

Type 2 diabetes mellitus with circulatory complication (E11.5)

Type 2 diabetes mellitus with diabetic cardiomyopathy (E11.53)

Users of the data cubes are likely to require some familiarity with ICD-9-CM and ICD-10-AM and have access to the full publications. This data access system does not allow searching on keywords or ICD-9-CM/ICD-10-AM codes. Users will generally need to know what chapter the information they are looking for is in, to work down to more specific levels of detail.

International Classification of Diseases (ICD)

Principal diagnoses are classified according to either the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) or the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM). The use of the different classifications (ICD-9-CM and ICD-10-AM) in the data cubes means that data for 1998–99 to 2013–14 may not be exactly comparable with data for 1993-94 to 1997-98.

In addition, there are some differences in the coding between editions and these will be reflected in the cube. Readers should refer to the National Centre for Classification in Health (NCCH) for information on how to access the full classification and for detailed information on the differences between ICD-9-CM, ICD-10-AM and the different editions of ICD-10-AM.

The following is a list of the ICD disease chapters and the code ranges covered by each:

Chapter

Disease classification

Code range

1

Certain infectious and parasitic diseases

A00–B99

2

Neoplasms

C00–D48

3

Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism

Confidentialty

In order to maintain confidentiality, some data have been suppressed. This has been applied at the three-digit/character level for the principal diagnosis data cubes.

Data have been suppressed for a particular diagnosis if:

there is a potential risk of identifying an individual

there are fewer than three reporting units (hospitals or states/territories where the hospitals are not individually identified), or

there are three reporting units and one contributed more than 85% of the total separations, or

there are three or more reporting units and two contributed more than 90% of the total separations.

Data for the suppressed categories will not appear in the data cubes, but will be included in the sub-chapter, chapter and grand totals. Thus, the sum of separation counts presented within a chapter or sub-chapter for some codes may not match the total.